Refrigerating apparatus



Filed-Feb. 1'?, 1930 IN VEN TOR.

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Patented Nov. 8, 1932 PATENT OFFICE .ARTHUR J. KERCHER, 011' BERKELEY, CALIFORNIA BEFBIGEBATIN G APPARATUS Application led February 17, 1930. Serial No. 429,037.

This invention relates generally to refrigerating apparatus utilizing a condensible in fluid refrigerant. It is particularly adapted for refrigerators of small capacity such as are used for domestic purposes.

It is an object of the invention to generally improve upon condensers employed in refrigerating apparat-us, whereby such condensers can be more readily manufactured and will be more effective to transfer heat from the compressed refrigerant to convection currents of air.

It is a further object of the invention to devise a refrigerator assembly having many structural advantages over refrigerator apparatus of the prior art, as for example ease of manufacture and simplicity, and which will also utilize convection currents of air to advantage both for the purpose of removing heat from the condenser and also from the motor compressor unit.

Further objects of the invention will appear from the following description in which the preferred embodiment of the invention has been set forth in detail in conjunction with the accompanying drawing. It is to be understood that the appended claims are to be accorded a range of equivalents consistent with the state of the prior art.

Referring to the drawing:

Figure 1 is a side elevational view in cross section illustrating a refrigerator constructed in accordance with the present invention.

Figure 2 is a fragmentary cross sectional view taken along the line 2 2 of Fig. 1.

In domestic refrigerators of the prlor art, it has been common to utilize a coiled metal tube as a condenser. By a condenser, I have reference to a heat exchanger for transferring heat from a compressed iuid refrigerantto a surroundingr fluid medium, as for eX- ample to convection currents of air. The disadvantage of a simple coiled tube type of condenser is that it has relatively small capacity compared to the amount of tubing employed. In refrigerators of the type in which the motor compressor unit is enclosed within a sealed metal casing, it has been common to support the coils of the condenser tube upon metal iins mounted upon the outer periphery of the casing. A condenser mounted this manner also has a relatively small capacity, and such an assembly is not as eiicient as the arrangement herein disclosed, in that a transfer of heat occurs from the metal casing to the condenser tube. v

In the present invention I likewise employ a metal tube coiled in the form of a helix,' but in place of relying upon transfer of heat to convection currents of air surrounding the tube, I mount the coils of the tube in good heat conducting contact with the inner surface of a hollow member, as for example a hollow metal cylinder. Cooling fins are` mounted upon the outer periphery of the hol- 05 low metal cylinder, so that heat is transferred from the coils of the tube thru the metal Walls of the hollow cylinder to the metal cooling fins. I also provide a novel assembly in which my condenser is mounted below an 70. enclosed metal casing containing the motor compressor unit.

Referring to the drawing the refrigerator shown therein, consists of a motor compressor unit 10 of suitable construction, mounted 75 Within a sealed metal casing 11. No particular motor compressor unit will be described in detail, since various types can be employed. The particular unit illustrated in outline in the drawing corresponds to the unit disclosed so in my copending application No. 430,563 filed Feb. 24, 1930. It may be described briefiy as compresing a suitable electrical motor 12 driving a rotary piston type compressor 13. The particular casing 11 illustrated consists of upper and lower sections 16 and 17, which can be made of spun metal, and which have their opposed edge portions 18 and 19 turned or rolled over as indicated. rIhese portions 18 and 19 serve to engage grooves formed on the opposite faces of an annular metal ring 21. Gaskets 22 between portions 18 and 19 and ring 21 serve to form an air tight seal. Pipe 24 forms a discharge connection for the 95, compressor, and pipe 26 forms an intake connection, both pipes 24 and 26 preferably extending to the exterior down thru the lower casing section 17. Electrical connection to the motor of the compressor unit is made thru loo electrical cable 27, which also extends down thru the lower casing section 17.

In the operation of a motor compressor unit serving to compress fluid refrigerant, considerable heat is developed which is transferred to the metal casing 11. In order to facilitate dissipating this heat to convection currents of air the upper casing section 16 is provided with a plurality of circumferentially spaced cooling fins 28 which have good heatl conducting contact with the metal walls of the casing, as by being soldered, welded or brazed thereto. Corresponding cooling fins 29 are similarly mounted upon the outer surface of the lower casing section 17. In order to aid in the mounting and spacing of the Cooling fins, an annular metal band or ring 31 -can be mounted in slots provided in fins 28,

and an annular ring 32 can be similarly mounted with respect to the lower ns 29. For securely clamping the two casing sections together, I can utilize a plurality of spaced tie rods 33, the lower ends of these rods being shown provided with hook portions 34 for engaging ring 32. I-Iook members 36 slidably engage the upper ends of rods 33, and are adapted to be clamped upon ring 31 by some thumb nuts 37. By removing tie rods 33 the upper casing section 16 can be'readily removed tcpermit servicing the motor compressor unit.

The preferred form of my condenser is indicated generally at 38 and is preferably mounted below the sealed casing 11. This condenser consists of a tube 39 which is coiled in the form of a helix, and which is made of some suitable metal having good heat conductivity, such as copper. The helix formed by this coiled pipe is disposed within a hollow metal cylinder 41 which is preferably normally arranged in an upright position as shown. In order to afford a good heat conducting contact between the metal walls of tube 39 and the walls of hollow cylinder 41,

a metal bond 42 is formed between the tubeand the inner surface of hollow cylinder 41, the bond being made of suitable metal such as solder. Upon the outer periphery of cylinder 41 I mount a plurality of upright circumferentially spaced metal cooling fins 43, the inner edges of these fins also having good heat conducting contact with the hollow cylinder 41, as by being soldered, brazed or welded thereto. One end 44 of condenser tube 39 is connected to the discharge or high pressure side of the motor compressor unit 10. The outlet end 46 of the condenser is connected to a receiver 47 which in turn is connected to the heat absorber 48 thru a suitable pressure reducing valve. According to general practice heat absorber 48 is placed within a refrigerating chamber, and serves to remove heat from the chamber and thus maintain'a low refrigerating temperature. The

volatilized uid from heat absorber 48 is returned to the compressor thru pipe 46.

In order that cylinder 41 may serve as a support for the casing 1l and the motor compressor unit, the upper part of is shown provided with an inturned extension 51 upon which the housing 11 is disposed. Apertures 52 and 53 permit passage of convection currents of air into cylinder 41 and in contact with the inner surfaces of tube 39.

Fins 43 form spaced upright passages 54 for passage of convection currents of air, and the air discharge from these passages is also caused to fiow upwardly between the cooling fins 28 and 29 of casing 11. In order to make passages 54 more effective to form iiues for convective currents of air. and in order to enhance the appearance of the complete refrigerator apparatus. I preferably surround the entire assembly with a cylindrical housing 56. The lower part of housing 56 is provided with a .base portion 57, which can be made integral with the material of the housing. The lower edge of the hollow cylinder 41 can also rest upon base portion 57 as shown. Lower apertures 58 permit convection currents of air to iow into housing 56, upwardly thru passages 54 between fins 43, and then thru the. passages or stages between fins 28 and 29 to be discharged to the atmosphere at the top of the housing.

In the operation of the apparatus described above the Huid condensible refrigerant, which can be any suitable fluid such as ammonia or ethyl chloride. is compressed by the motor compressor unit 10. and discharged into the condenser tube 39 thru pipe 24. Heat from the fluid in the condenser tube is transmitted thru the walls of the tube to the metal cylinder 41 and to the. metal cooling fins 43. Convection currents of air are therefore induced to iiow upwardly thru passages 54 to effectively remove. heat from the fins and from the outer surface of cylinder 41. As these convection currents leave fins 43 they flow upwardly thru fins 28 and 29 thus also serving to remove heat from these fins to keep the motor compressor unit at a safe temperature. The superposed relationship of fins 28 and 29, with respecttofins43,causesan augmented or more rapid upward movement of convection currents of air. than could be obtained merely by the use of fins 43 alone. Because of the large surface area exposed to convection currents of air and because 'of the good heat conducting contact between tubes 39, cylinder,41. and the fins 43. the transfer of heat to convection currents of air is made highly efficient and with a minimum temperature drop. It is also evident that the condenser as described can be readily manufactured and assembled, since it requires only simple operation to properly bondthe tube 39 with the inner surface of cylinder 41. and to bond fins 43 to the outer surface of the cylinder.

this cylinder I claim:

l. In a refrigerator, a. condenser comprising a hollow metal member, a tube adapted to conduct refrigerant to be condensed and coiled within said member, said tube being -in good heat conducting Contact with said member and cooling fins disposed on the outer surface of said member and in good heat conducting contact with the same.

2. In a refrigerator, a condenser comprising a hollow metal member, a tube adapted to conduct refrigerant to be condensed and coiled within said member, convolutions of said tube having a metal bond with the inner wall of said member, and cooling fins disposed on the outer surface of said member, said ins defining upwardly extending passages for convection currents of air and bein in good heat conducting contact with the metal of said member.

3. In a refrigerator, a hollow metal cylinder, a tube coiled in the form of a helix into which refrigerant to be condensed is introduced, the outer surfaces of said helix having a metal bond with the inner surface of said cylinder, and heat dissipating fins disposed upon the exterior of the cylinder and in good heat conducting contact with the same.

4. In a refrigerator, a condenser comprising a hollow metal member, a tube adapted to conduct refrigerant to be condensed and coiled within said member, said tube being in good heat conducting contact with said member, cooling fins disposed on the outer surface of said member and in good heat conducting contact with the same, said fins defining upwardly extending passages for convection currents of air, and the upper outer surface of said hollow member being adapted to form a support for a compressor for the refrigerant conducted to said tube.

In testimony whereof, I have hereunto set my hand.

ARTHUR J. KERCHER. 

